Field
The present disclosure relates generally to electronic circuits, and more particularly, to switchable decoupling capacitors.
Background
Recent advancements in manufacturing processes for integrated circuits have enabled designers to integrate all components of a computer or other electronic system onto a single monolithic integrated circuit known as a “System-on-a-Chip” (SOC). These integrated circuits are often used in mobile battery powered devices such as cellular phones, smart phones, personal digital assistants, embedded systems, laptop computers, media players, electronic gaming systems, global positioning systems, sensors, or any other suitable devices. Depending on the device, the SOC may include various digital and analog circuits that perform various functions. For example, an SOC may include processors, controllers, graphics, video circuits, audio circuits, wireless modems, networking circuits, memories, peripheral interface circuits, bus interface circuits, sensors, detectors, user interfaces, and/or other suitable circuits.
As the demand for more processing capability continues to expand, there is an ever increasing need for effective power management systems to reduce power consumption and thereby conserve battery life in mobile devices. Various techniques have been employed. One such technique involves operating certain circuits in a low power or sleep mode when not in use. This technique reduces power consumption, but may adversely affect transient voltage levels when a circuit transitions from the sleep to the active mode. Specifically, the instantaneous increase in current required by the transitioning circuit can cause a sudden voltage drop to other circuits on the SOC. Decoupling capacitors are often used to supply this current to a transitioning circuit to help maintain a constant voltage across other circuits. However, decoupling capacitors occupy a considerable amount of surface area on the SOC. Accordingly, there is a need in the art for decoupling capacitors with a small footprint that reduce variations in transient voltage levels.